We theoretically analyze the influence of magnetic field on small-signal absorption and gain in a superlattice. We predict a very large and tunable THz gain due to nonlinear cyclotron oscillations in crossed electric and magnetic fields. In contrast to Bloch gain, here the superlattice is in an electrically stable state. We also find that THz Bloch gain can be significantly enhanced with a perpendicular magnetic field. If the magnetic field is tilted with respect to the superlattice axis, the usually unstable Bloch gain profile becomes stable in the vicinity of Stark-cyclotron resonances.
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http://dx.doi.org/10.1103/PhysRevLett.103.117401 | DOI Listing |
Adv Mater
January 2025
School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China.
Van der Waals (vdWs) materials are promising candidates for hetero-integration with silicon photonics toward miniaturization and integration. VdWs materials like molybdenum telluride and black phosphorus, despite being prominent, exhibit air sensitivity, and their room temperature emissions can be significantly broadened by tens of meV. Here, a self-encapsulation strategy is developed to scalably synthesize robust 2D vdWs ErOCl with sub-meV narrow emissions at the telecom C-band.
View Article and Find Full Text PDFAdv Mater
January 2025
State Key Laboratory for Manufacturing Systems Engineering, Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education, School of Electronic Science and Engineering, Xi'an Jiaotong University, Xi'an, 710049, China.
Large low-field magnetoresistance (LFMR, < 1 T), related to the spin-disorder scattering or spin-polarized tunneling at boundaries of polycrystalline manganates, holds considerable promise for the development of low-power and ultrafast magnetic devices. However, achieving significant LFMR typically necessitates extremely low temperatures due to diminishing spin polarization as temperature rises. To address this challenge, one strategy involves incorporating Ruddlesden-Popper structures (ABO):AO, which are layered derivatives of perovskite structure capable of potentially inducing heightened magnetic fluctuations at higher temperatures.
View Article and Find Full Text PDFSmall
January 2025
School of Energy Science and Engineering, Indian Institute of Technology Kharagpur, Kharagpur, 721302, India.
Inducing magnetic ordering in a non-ferrous layered double hydroxides (LDHs) instigates higher spin polarization, which leads to enhanced efficiency during oxygen evolution reaction (OER). In nano-sized magnetic materials, the concept of elongated grains drives domain alignment under the application of an external magnetic field. Hence, near the solid electrode interface, modified magnetohydrodynamics (MHD) positively impacts the electrocatalytic ability of non-ferrous nanocatalysts.
View Article and Find Full Text PDFAdv Mater
January 2025
Department of Applied Physics, University of Tokyo, Bunkyo-ku, Tokyo, 113-8656, Japan.
Antiferromagnets with broken time-reversal ( ) symmetry ( -odd antiferromagnets) have gained extensive attention, mainly due to their ferromagnet-like behavior despite the absence of net magnetization. However, certain types of -odd antiferromagnets remain inaccessible by the typical ferromagnet-like phenomena (e.g.
View Article and Find Full Text PDFPhys Rev B
January 2018
Quantum Electromagnetics Division, National Institute of Standards and Technology, Boulder, CO 80305, U.S.A.
Understanding the evolution of spin-orbit torque (SOT) with increasing heavy-metal thickness in ferromagnet/normal metal (FM/NM) bilayers is critical for the development of magnetic memory based on SOT. However, several experiments have revealed an apparent discrepancy between damping enhancement and damping-like SOT regarding their dependence on NM thickness. Here, using linewidth and phase-resolved amplitude analysis of vector network analyzer ferromagnetic resonance (VNA-FMR) measurements, we simultaneously extract damping enhancement and both field-like and damping-like inverse SOT in NiFe/Pt bilayers as a function of Pt thickness.
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